This invention relates to transportation seating and more particularly to a unique seat for use in a passenger carrying vehicle which is capable of absorbing impact energy imposed thereon by a passenger seated behind the seat during a crash or rapid maneuver.
In recent years, efforts have been made to improve the crash worthiness of mass transportation vehicles such as school, intercity, intracity and interurban buses, trains and/or aircraft. Crash studies particularly in the ground transportation industry have shown that one of the major causes of injury to passengers in an accident is the result of being impacted or thrown into the seat structures. The seats typically fail to protect the passengers by being too weak, too low or too hostile. In a conventional mass transportation vehicle, such as a bus, passengers are thrown from their seats forwardly into the next adjacent seat. If the seat back of the next adjacent seat is too low, they could be catapulted over the top of the seat and impact the interior of the vehicle with severe injury. Further, if the seat structure against which they impact is too weak or is incapable of absorbing sufficient energy in a controlled manner, the seat structure may fail similarly permitting the passenger to be thrown forward resulting in severe injury. Efforts have been made to reduce the hostility of the seats by removing or redesigning articles such as grab rails or the leg structures of the seats which during a crash situation could become blunt or sharp instruments capable of inflicting severe and sometimes fatal injury to the passengers.
In the mass transportation industry, and particularly, school buses, active restraint systems such as seatbelts have not received ready acceptance due primarily to the nature of the vehicles involved and their uses. Due to the large number of passengers, it is extremely difficult to enforce the use of seatbelts. Therefore, the trend has been to provide for crashworthiness through passive restraint systems. Passive systems are preferred in many applications and in particular in school buses. Due to the age of the children and the nature of school bus use, it would be impractical to require a single school bus driver to ensure that active restraints such as seatbelts were employed by the children.
In order to increase the safety of vehicles and, in particular school buses, efforts have been directed to arrange the interiors so that the passengers are compartmentalized. Each compartment would include the interior side wall of the vehicle, the passengers own seat and the seat immediately in front of the passenger. The design emphasis on the seats themselves has been to provide a seat which is capable of absorbing impact energy in a controlled manner within certain levels so as to reduce or prevent the occurrence of and the severity of injuries to the passengers.
In an effort to provide crash protection and in accordance with the mandate set forth in the National Motor Vehicle Safety Act of 1966, 15 U.S.C. 1381 et seq, as amended by Public Law 93-492 in 1974, the National Highway Traffic Safety Administration promulgated Docket Number 73-3 Notice 5 which is now 49 C.F.R. 571, Standard 222. This Docket is entitled SCHOOL BUS PASSENGER SEATING AND CRASH PROTECTION and sets forth certain criteria relating to energy absorption and compartmentalization characteristics which must be met by school bus seating.
Attempts have been made to fabricate seats in accordance with the aforementioned Docket criteria. Typically, these seats have employed large amounts of padding or energy absorbing material to meet the required standards. The resulting seats have been aesthetically unpleasing and possess the disadvantages of relatively high weight when compared to previously employed seats and relatively complex construction and bulkiness. These seats also suffer from relative high cost of manufacture and installation.
Design work has been conducted in the area of the leg structures which support the seat frame to increase their energy absorption characteristics and to prevent catastrophic failure which would turn the leg structure into a hostile instrument. An example of one such transportation seat including a pedestal structure which increases the energy absorption characteristics of the seat may be found in U.S. Pat. No. 3,729,226, entitled SINGLE PEDESTAL TRANSIT CHAIR and issued on Apr. 24, 1973 to the present inventor. This seat incorporates an inverted "T" support pedestal including an upright column member connected to the seat frame and an integral, hollow tubular foot member extending fore and aft of the chair or seat from the bottom of the column member. During a crash situation, the inverted "T" tubular pedestal is deformed thereby absorbing the energy of impact resulting in reduced occurrence of and severity of injury to the passengers. The single pedestal transportation seat disclosed in this patent, although a significant improvement, was found to be incapable of satisfying the force/deflection criteria promulgated by the National Highway Traffic Safety Administration in the aforementioned Docket Number 73-3; Notice 5.
A need therefore, exists for an improved transportation seat which is capable of absorbing the energy of impact in a crash situation so as to reduce or eliminate injury to passengers. Such a seat would preferably be aesthetically pleasing in appearance, readily adaptable to a wide variety of existing bus structures as well as new design bus interior arrangements or other transportation vehicles while being relatively easy to manufacture with little or no increase in cost when compared to presently available seating and which does not suffer from the aforementioned disadvantages.